FIGURE 5.
Current-voltage relationship of mammalian InsP3R isoforms. InsP3R currents were recorded in the planar lipid bilayers in the range of transmembrane potentials from −30 mV to +10 mV (cis versus trans). Single-channel current amplitude at each voltage was determined from a Gaussian fit as shown in Figs. 2 B, 3 B, and 4 B. The data for RT1 (○), RT2 (▴), and RT3 (•) are shown as means ± SE (n ≥ 3). The slope of the linear fit to the data (lines; r = 0.99) yielded a single-channel conductance of 80 pS for RT1, 78 pS for RT2, and 74 pS for RT3.